Stream metabolism, often referred to as aquatic ecosystem metabolism in both freshwater (lakes, rivers, wetlands, streams, reservoirs) and marine ecosystems, includes gross primary productivity (GPP) and ecosystem respiration (ER) and can be expressed as net ecosystem production (NEP = GPP - ER). Analogous to metabolism within an individual organism, stream metabolism represents how energy is created (primary production) and used (respiration) within an aquatic ecosystem. In heterotrophic ecosystems, GPP:ER is <1 (ecosystem using more energy than it is creating); in autotrophic ecosystems it is >1 (ecosystem creating more energy than it is using).[1] Most streams are heterotrophic.[2] A heterotrophic ecosystem often means that allochthonous (coming from outside the ecosystem) inputs of organic matter, such as leaves or debris fuel ecosystem respiration rates, resulting in respiration greater than production within the ecosystem. However, autochthonous (coming from within the ecosystem) pathways also remain important to metabolism in heterotrophic ecosystems. In an autotrophic ecosystem, conversely, primary production (by algae, macrophytes) exceeds respiration, meaning that ecosystem is producing more organic carbon than it is respiring.
Stream metabolism can be influenced by a variety of factors, including physical characteristics of the stream (slope, width, depth, and speed/volume of flow), biotic characteristics of the stream (abundance and diversity of organisms ranging from bacteria to fish), light and nutrient availability to fuel primary production, organic matter to fuel respiration, water chemistry and temperature, and natural or human-caused disturbance, such as dams, removal of riparian vegetation, nutrient pollution, wildfire or flooding.
Measuring stream metabolic state is important to understand how disturbance may change the available primary productivity, and whether and how that increase or decrease in NEP influences foodweb dynamics, allochthonous/autochthonous pathways, and trophic interactions. Metabolism (encompassing both ER and GPP) must be measured rather than primary productivity alone, because simply measuring primary productivity does not indicate excess production available for higher trophic levels. One commonly used method for determining metabolic state in an aquatic system is daily changes in oxygen concentration, from which GPP, ER, and net daily metabolism can be estimated.
Disturbances can affect trophic relationships in a variety of ways, such as simplifying foodwebs, causing trophic cascades, and shifting carbon sources and major pathways of energy flow (Power et al. 1985, Power et al. 2008). Part of understanding how disturbance will impact trophic dynamics lies in understanding disturbance impacts to stream metabolism (Holtgrieve et al. 2010). For example, in Alaska streams, disturbance of the benthos by spawning salmon caused distinct changes in stream metabolism; autotrophic streams became net heterotrophic during the spawning run, then reverted to autotrophy after the spawning season (Holtgrieve and Schindler 2011). There is evidence that this seasonal disturbance impacts trophic dynamics of benthic invertebrates and in turn their vertebrate predators (Holtgrieve and Schindler 2011, Moore and Schindler 2008). Wildfire disturbance may have similar metabolic and trophic impacts in streams.
Odum, Howard T., "Primary production in flowing waters", Limnology and Oceanography, vol. 1, no. 2, pp. 102–117, April 1956.
Power, M. E.; Matthews, W. J.; Stewart, A. J., "Grazing minnow, piscivorous bass, and stream algae: dynamics of a strong interaction", Ecology, vol. 66, pp. 1448–1456.
Holtgrieve, Gordon W.; Schindler, Daniel E.; Branch, Trevor A.; A’mar, Z. Teresa, "Simultaneous quantification of aquatic ecosystem metabolism and reaeration using a Bayesian statistical model of oxygen dynamics", Limnology and Oceanography, vol. 55, no. 3, pp. 1047–1063, 2010.
Holtgrieve, Gordon W.; Schindler, Daniel E., "Marine-derived nutrients, bioturbation, and ecosystem metabolism: reconsidering the role of salmon in streams", Ecology, vol. 92, pp. 373–385.
Moore, Jonathan W.; Schindler, Daniel E., "Biotic disturbance and benthic community dynamics in salmon-bearing streams", Journal of Animal Ecology, vol. 77, iss. 2, pp. 275–284, March 2008.
December 15, 2023
stream, metabolism, often, referred, aquatic, ecosystem, metabolism, both, freshwater, lakes, rivers, wetlands, streams, reservoirs, marine, ecosystems, includes, gross, primary, productivity, ecosystem, respiration, expressed, ecosystem, production, analogous. Stream metabolism often referred to as aquatic ecosystem metabolism in both freshwater lakes rivers wetlands streams reservoirs and marine ecosystems includes gross primary productivity GPP and ecosystem respiration ER and can be expressed as net ecosystem production NEP GPP ER Analogous to metabolism within an individual organism stream metabolism represents how energy is created primary production and used respiration within an aquatic ecosystem In heterotrophic ecosystems GPP ER is lt 1 ecosystem using more energy than it is creating in autotrophic ecosystems it is gt 1 ecosystem creating more energy than it is using 1 Most streams are heterotrophic 2 A heterotrophic ecosystem often means that allochthonous coming from outside the ecosystem inputs of organic matter such as leaves or debris fuel ecosystem respiration rates resulting in respiration greater than production within the ecosystem However autochthonous coming from within the ecosystem pathways also remain important to metabolism in heterotrophic ecosystems In an autotrophic ecosystem conversely primary production by algae macrophytes exceeds respiration meaning that ecosystem is producing more organic carbon than it is respiring Stream metabolism can be influenced by a variety of factors including physical characteristics of the stream slope width depth and speed volume of flow biotic characteristics of the stream abundance and diversity of organisms ranging from bacteria to fish light and nutrient availability to fuel primary production organic matter to fuel respiration water chemistry and temperature and natural or human caused disturbance such as dams removal of riparian vegetation nutrient pollution wildfire or flooding Measuring stream metabolic state is important to understand how disturbance may change the available primary productivity and whether and how that increase or decrease in NEP influences foodweb dynamics allochthonous autochthonous pathways and trophic interactions Metabolism encompassing both ER and GPP must be measured rather than primary productivity alone because simply measuring primary productivity does not indicate excess production available for higher trophic levels One commonly used method for determining metabolic state in an aquatic system is daily changes in oxygen concentration from which GPP ER and net daily metabolism can be estimated Disturbances can affect trophic relationships in a variety of ways such as simplifying foodwebs causing trophic cascades and shifting carbon sources and major pathways of energy flow Power et al 1985 Power et al 2008 Part of understanding how disturbance will impact trophic dynamics lies in understanding disturbance impacts to stream metabolism Holtgrieve et al 2010 For example in Alaska streams disturbance of the benthos by spawning salmon caused distinct changes in stream metabolism autotrophic streams became net heterotrophic during the spawning run then reverted to autotrophy after the spawning season Holtgrieve and Schindler 2011 There is evidence that this seasonal disturbance impacts trophic dynamics of benthic invertebrates and in turn their vertebrate predators Holtgrieve and Schindler 2011 Moore and Schindler 2008 Wildfire disturbance may have similar metabolic and trophic impacts in streams See also editOverflow metabolism Lake metabolism Apparent oxygen utilisationReferences editOdum Howard T Primary production in flowing waters Limnology and Oceanography vol 1 no 2 pp 102 117 April 1956 Power M E Matthews W J Stewart A J Grazing minnow piscivorous bass and stream algae dynamics of a strong interaction Ecology vol 66 pp 1448 1456 Holtgrieve Gordon W Schindler Daniel E Branch Trevor A A mar Z Teresa Simultaneous quantification of aquatic ecosystem metabolism and reaeration using a Bayesian statistical model of oxygen dynamics Limnology and Oceanography vol 55 no 3 pp 1047 1063 2010 Holtgrieve Gordon W Schindler Daniel E Marine derived nutrients bioturbation and ecosystem metabolism reconsidering the role of salmon in streams Ecology vol 92 pp 373 385 Moore Jonathan W Schindler Daniel E Biotic disturbance and benthic community dynamics in salmon bearing streams Journal of Animal Ecology vol 77 iss 2 pp 275 284 March 2008 Retrieved from https en wikipedia org w index php title Stream metabolism amp oldid 1054277821, wikipedia, wiki, book, books, library,
